Joint of concrete building elements

ABSTRACT

The joint of concrete building elements includes a system of connecting pins (2), formed by rows of mutually parallel bars, the central parts of which cross the area end sections, concreted in mutually joined building elements. The connecting pins (2) are arranged in a brush system in at least one row in particular, however, into a group of mutually parallel rows of the connecting pins (2) arranged one over the other. The system of connecting pins (2) is concreted, in part of its length, into the contact surfaces of the supporting column head (1), from which the protruding second sections of the length of connecting pins (2) are concreted in the ceiling structure, particularly in the ceiling slab (3) and/or in ceiling girders (4).

FIELD OF THE ART

The invention relates to a joint of concrete building elementscomprising, in the area of contact of concrete elements, shearingsupporting parts for transfer of shearing forces.

STATE OF THE ART

When placing a horizontal ceiling structure onto point or linearsupports, particularly supporting columns or supporting walls of abuilding structure, it is above all necessary to ensure a reliabletransfer of shearing forces from a horizontal supporting structure intoa vertical supporting structure of the column. The most popularresolution of this problem are beam ceiling structures, at which loadsfrom a ceiling slab are transferred into ceilings beams or girders whichhave a sufficient cross sectional area to transfer shearing forces andwhich are, in addition, supported by an appropriate arrangement ofshearing reinforcement in the form of bents of reinforcing bars andwhich are then mounted onto vertical supporting columns, in particular,by mounting ceiling beams directly onto heads of sectioned columns,brackets joined to heads of columns or into recesses formed insupporting columns. The disadvantages of such beam ceiling structuresare well known and are due to the tall constructional height of theceiling structure which diminishes the useful height of a buildingstructure storey and causes further problems related to technologicaldistribution and similar systems.

The disadvantage of the tall structural height of beam ceilingstructures may be obviated by means of a flat-slab ceiling construction,where a ceiling slab is mounted on pyramid or truncated-conical shapedceiling heads, the smaller base of which is connected to supportingcolumns heads and the bigger base of which forms a supporting surfacefor the ceiling slab mounting or part of the ceiling slab itself.

The Czech patent 144 928 has introduced a monolithic reinforced concreteceiling, consisting of a monolithic reinforced concrete slab mounted onprefabricated column heads formed by truncated-conical or flatcylindrical heads the thickness of which basically corresponds with thethickness of the ceiling slab. The central part of the heads are joinedto supporting columns heads and to increase their shearing bearingpower, they are pre-stressed by means of a constructional arrangementwhereby a circumferential cylindrical surface of heads is provided witha circumferential semi-groove in which a wrapped circumferentialpre-stressed reinforcement is mounted, and under which radial bars whichare fixed by wrapping are mounted to transfer shearing stresses.

A further improvement of this answer to a girderless ceiling structureconsists of a monolithic ceiling slab around the ceiling head which isreinforced with a spiral reinforcement and which should ensure a perfectjoint of the monolithic ceiling slab and of a prefabricated ceilingprestressed head, as well as transfer of shearing forces into theceiling head. A disadvantage this solution is due to the complicatedproduction process of pre-stressed ceiling heads, making them expensiveand thus increasing the costs of ceiling structures.

Therefore, the invention aims to provide an answer to joining reinforcedconcrete structures and elements, particularly a horizontal ceilingstructure, with vertical supporting elements where the transfer ofshearing forces between both joined building elements and structureswould be ensured by simple jointing means which are neither complicatednor expensive.

BACKGROUND OF THE INVENTION

This task has been resolved by a joint of concrete building elementsaccording to the invention, the principle of which consists in the factthat shearing supporting parts constitute a brush system of connectingpins, formed by several rows of mutually parallel bars; their centralpart crosses the area of contact of joined building elements and bothend sections are concreted in the mutually joined building elements.

In an advantageous embodiment of the joint according to the invention,the radial connecting pins in a brush system are arranged in at leastone horizontal row, particularly in a group of mutually parallel rows ofconnecting pins one above the other. The brush system of connecting pinsare anchored in joined building elements at an acute angle of 30° to 60°with the vertical plane.

In another advantageous embodiment of the joint according to theinvention, a part of the system of connecting pins is concreted insurfaces of contact in the head of the supporting column, from which theother sections of the length of the connecting pins are concreted in theceiling structure, especially in a ceiling slab and/or in ceilinggirders.

In another advantageous embodiment of the invention, the supportingcolumn, in its area of contact, is provided with a circumferential rimin the form of a circumferential recess in the supporting collar of adepth of 10 mm to 40 mm, and of a height which corresponds with thethickness of the adjoining ceiling structure; the systems of connectingpins protrude from the bottom of the circumferential rim of thesupporting column.

During the manufacture of the column, which is a part of the jointaccording to the invention, it is convenient to prefabricate the brushsystem of connecting pins which are formed by steel assembly platesconcreted into the bottom of the circumferential rim of the supportingcolumn and having a system of holes through which the connecting pins,joined to steel plates pass and one part of the length of which areconcreted into the supporting columns. In an advantageous embodiment ofthe invention, the connecting pins are formed of parts of steel ropesseparated by burning.

In an alternative advantageous embodiment of the joint according to theinvention, the connecting pins, arranged in the radial brush system andprotruding from the supporting column, are inserted in the brush systemof connecting pins protruding from the joined areas of contact of theceiling structure.

The joint for concrete building elements according to the invention maybe used for joining and contacting any building elements, parts andstructures, where it is necessary to ensure a transfer of shearingforces. Its advantages are most evident in joints of a supporting columnto a ceiling slab, where such a joint consists of a simpler, cheaper andless complicated mounting of a thin ceiling slab onto a point supportand where sufficient measures have been taken to prevent the columnpunching of slab.

LIST OF DRAWINGS

The invention will be described in more detail by means of embodimentsof the joint for two parts of a building structure, illustrated indrawings, where:

FIG. 1 shows a vertical section of a joint of a vertical prefabricatedcolumn to a monolithic reinforced concrete ceiling slab;

FIG. 2 shows a horizontal section of a joint of a vertical prefabricatedcolumn to a cut-out of a monolithic reinforced concrete ceiling slab;

FIG. 3 shows a vertical section of a joint of a vertical supportingcolumn to a horizontal ceiling girder;

FIG. 4 shows a horizontal section of a joint of a vertical supportingcolumn to a ceiling beam or girder; and

FIG. 5 shows a side view to a prefabricated system of connecting pins,fixed onto a common steel plate.

PREFERRED EMBODIMENTS OF THE INVENTION

In the first example of the embodiment of the joint of two parts of abuilding structure according to the invention, one of the parts beingjoined is a supporting column 1 and the other part being joined is amonolithic ceiling slab 3. In the joint, it is necessary to transfershearing forces from the ceiling slab 3 to the supporting column 1.FIGS. 1 and 2 show the area of a supporting column joint, in thisexample, in the form of a prefabricated element passing through areinforced concrete monolithic ceiling slab 3 with an even surfacethickness of 10-20 cm. Only a small shearing surface is available forthe transfer of shearing forces from monolithic ceiling slab 3 at thepoint of contact with supporting column 1, so that to allow a transferof the shearing forces, there must be a special constructionaladaptation in the joint area to prevent ceiling slab 3 being pierced bysupporting column 1 due to its own weight and of useful loading from theceiling structure.

This constructional adaptation consists of the supporting column 1, inthis example a passing prefabricated column, being provided, at thelevel where it joins the ceiling slab 3 and in the area of itscircumferential surfaces of contact, with a group of radial brushconnecting pins 2, which are set in concrete up to half their length inthe supporting column 1 while the remaining length protrudes radiallyand obliquely upwards from the circumferential surfaces of contact ofthe supporting column 1 and crosses the shearing gap at the point whereceiling slab 3 joins supporting column 1. In this example of theinvention, each system of brush connecting pins 2, arranged on each sidewall of supporting column 1, is formed by six horizontal rows ofconnecting pins 2 arranged one above the other; each row comprises fiveconnecting pins 2. The connecting pins 2 are conveniently made e.g. ofpieces of pull-rods, or cuttings from reinforcing bars. Each of theconnecting pins forms an angle of 45° and is placed in a vertical planeparallel to the respective side wall of the supporting column 1 having arectangular cross section.

In order further to improve transfer of shearing forces from the ceilingstructure into the supporting column 1, the supporting column 1 has, inthe area of the joint, a circumferential rim 5 formed by acircumferential recess in the circumferential surfaces of the supportingcolumn 1 about 30 mm deep with a height corresponding with the thicknessof the ceiling slab 3 of the ceiling structure.

During the manufacture of this joint in accordance with the invention,the prefabricated passing supporting columns 1 are fitted with theconcreted systems of connecting pins 2 and form a casing of the lowersurface of the concrete supporting slab of the ceiling slab 3 at thelevel of the lower edge of the circumferential rim 5. This casing isthen mounted with and joined to the reinforced ceiling slab 3 which isadapted in the supporting column 1 area by the dimensions of reinforcingbars and arrangement thereof in order to work together with the systemsof connecting pins 2 and to transfer shearing forces onto the connectingpins 2 and to the circumferential rim 5 area of the supporting column 1;whereupon the reinforced concrete ceiling slab 3 should beconcreted--the protruding ends of the connecting pins systems 2 are thenrun into this ceiling slab upon completion of concreting. The connectingpins 2 are easily held in the desired position during manufacture of theprefabricated supporting column 1, because it is sufficient to mount thecasing board, which forms the bottom of the circumferential rim 5, witha system of oblique holes, whose displacement and incline of axescorrespond with the displacement and position of the connecting pins 2in the brush system. An alternative embodiment of the casing board whichremains part of the joint is described in further detail in theclarification of the example of the embodiment in FIG. 5.

The joint according to the invention may be used for various kinds ofjoined structures, particularly vertical supporting structures withhorizontal supporting structures, e.g. it may be applied to a joint ofthe supporting column 1 with the ceiling girder 4, or with a beam in amonolithic or prefabricate embodiment, as it is shown in FIGS. 3. and 4.In this example of the embodiment, the vertical prefabricated passingsupporting column 1 is of the same embodiment as the supporting column 1shown in FIGS. 1. and 2. and by means of the joint according to theinvention it is joined, in this example of the embodiment, to theprefabricated ceiling girder 4 from the face of which a similar brushsystem of connected pins protrudes, i.e., the system comprises thirtyconnecting pins 2 arranged in six rows, one above the other and withfive connecting pins 4 in every row: these connecting pins 2 arearranged parallel to the connecting pins 2 which protrude from thesupporting column 1, i.e. so that they protrude from the face of theceiling girder 4--obliquely downwards, and they are mounted among theconnecting pins 2 protruding from the side walls of the supportingcolumn 1.

Upon the prefabricated ceiling girder 4 being mounted to the supportingcolumn 1 which has, in this example of the embodiment, a circumferentialrim 5, the space between the face of the ceiling girder 4 and walls ofthe circumferential rim 5 is filled with grout 6.

The concreting of connecting pins 2 into prefabricated supportingcolumns 1 or ceiling girders 4 is considerably facilitated by anassembly plate 7 shown in FIG. 5, and formed by a rectangular steelplate with a system of oblique holes 8 the axes of which incline withrespect to the assembly plate 7 at the same angle as that at which theconnecting pins 2 are to be mounted. The connecting pins 2 are insertedinto the oblique holes 8 in such a way that their centre passes throughthe holes 8 and each half is directed outwards from the assembly plate7. The centre part of the connecting pins 2 may be fixed in the holes 8e.g. by welding, whereupon the assembly plate 7 may be mounted into thecasing of the supporting column 1 so that it forms the bottom of thecircumferential rim 5 of the supporting column 1, the casing, includingthe required number of assembly plates 7 keeping the connecting pins 2in the desired positions during concreting, may then be grouted with aconcrete mix.

The joint according to the invention may be applied in many otherspecific instances involving a joint of, in particular, prefabricatedconstruction elements to a monolithic structure or to otherprefabricated construction elements, if the requirement is to ensure areliable transfer of shearing forces at the point of the joint. Forinstance, by use of connecting pins, arranged in brush systems, it ispossible to joint a concrete wall to a ceiling slab, or to anotherceiling structure where connecting pins protrude from the wall along itswhole upper joining section, or may be used for a shearing joint of twoparallel wall elements and so on.

We claim:
 1. A joint of concrete building elements in particular fortransferring of shearing forces, comprising:a plurality of substantiallyparallel connecting pins passing through contact areas of the joinedbuilding elements, the plurality of connecting pins are secured in oneof the joined building elements and extend into a single recess in saidone of the joined building elements, and the connecting pins beinginclined with respect to these joined building elements and formingacute angles directed in the opposite direction of the resultantshearing component of the forces for which the joint has been designed.2. The joint according to claim 1, wherein the connecting pins areparallel to one another.
 3. The joint according to claim 1, wherein thesize of the acute angle is 30° to 60°.
 4. The joint according to claim1, wherein the connecting pins are arranged in at least one horizontalrow or at least one vertical row.
 5. The joint according to claim 1,wherein the connecting pins are concreted for some of their length intothe contact areas of the head of a supporting column protruding fromwhich are other sections of the length of the connecting pins concretedinto a ceiling structure.
 6. The joint according to claim 5, wherein thesupporting column is provided with a circumferential rim in the form ofa circumferential recess of the supporting column having a depth of 10to 40 mm and a height corresponding with a thickness of the ceilingstructure, so that the plurality of connecting pins protrude from abottom of the circumferential recess of the supporting column.
 7. Thejoint according to claim 6 wherein the bottom of the circumferentialrecess is formed by steel assembly plates concreted into the recesssection and provided with a plurality of oblique holes passing throughwhich are the connecting pins which are fixed to steel assembly plates.8. The joint according to claim 5, wherein the ceiling structure is aceiling slab or ceiling girders.
 9. A joint of concrete buildingelements comprising:a column having a single recess formed on at leastone side of the column; a plurality of connecting pins positioned in therecess and concreted into the column, the connecting pins arrangedsubstantially parallel to one another and forming acute angles with thecolumn directed in the opposite direction of a resultant shearingcomponent of forces for which the joint has been designed; and abuilding element connected to the Column at the recess by the pluralityof connecting pins.
 10. The joint according to claim 9, wherein theacute angles are about 30° to about 60°.
 11. The joint according toclaim 9, wherein the building element is a ceiling structure.
 12. Thejoint according to claim 9, wherein the recess extends around a completecircumference of the column.
 13. The joint according to claim 12,further comprising a plate positioned in a bottom of the recess andhaving angled holes receiving the plurality of connecting pins.
 14. Thejoint according to claim 9, further comprising a plate positioned in abottom of the recess and having angled holes receiving the plurality ofconnecting pins.